I don't think any other team will compete with PSG for the Ligue 1 title this season. Marseille and Monaco played very well at the beginning of the season. But both of these teams are now far behind. Marseille is 7 points behind PSG and Monaco is 10 points behind. It will not be possible for these teams to close such a big gap. Moreover, Monaco and Marseille's performance is not consistent.
Although PSG has lost points in a few matches, PSG is still undefeated in Ligue 1. Now Luis Enrique's goal is to do well in the Champions League. So maybe PSG may lose points in a few more matches in Ligue 1. However, PSG will not suffer much from this. PSG will win the Ligue 1 title this season as well.
PSG rarely experience competition in Ligue 1, as soon as they have some more or less worthy opponent, they immediately sell their players and become uncompetitive the next season, because for them it is just a business. And PSG sets completely different goals, they strive to win all the tournaments, only with the Champions League they have difficulties. Now Enrique will try to strengthen the attack of PSG, maybe he will succeed if they make several good transfers, but even without this no one will overtake them in Ligue 1.
I don't know where got the record of PSG selling their players because of money; your statement makes me think that you are talking about Arsenal under Arsene Wenger who was famous for grooming players to sell at huge profits thereby making the club remain wealthy even though they rarely won trophies.
PSG have been the club with a good assembly of quality players in the likes of Messi and Neymar including Angel Di Maria and Mbappe. These are big names that played in the same club at a time so that idea of selling players because of money is not a PSG thing.